A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

The final resting place of the tragic king and queen of the Jazz Age is tucked away in a small Maryland graveyard.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

A museum dedicated to exhibiting remarkable outsider art.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

A former major munitions plant that has been converted into a sprawling art space.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

One street divides a single town that stands in two U.S. states.

America's first federal monument.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

Parking garage where Bob Woodward met Watergate source "Deep Throat."

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

An obscure federal monument honors the French diplomat who served as Ambassador to the U.S. during WWI.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.